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@PHDTHESIS{Baghdasaryan:348992,
      author       = {Baghdasaryan, Baghdasar},
      title        = {{S}patio-spectral engineering of entangled and single
                      photons in parametric down-conversion},
      school       = {Friedrich-Schiller-Universität Jena},
      type         = {Dissertation},
      address      = {Jena},
      publisher    = {Thüringer Universitäts- und Landesbibliothek Jena},
      reportid     = {GSI-2024-00453},
      pages        = {103 S.},
      year         = {2023},
      note         = {Dissertation, Friedrich-Schiller-Universität Jena, 2023},
      abstract     = {Photon pairs generated through SPDC inherently exhibit
                      spatio-spectral coupling, which implies that photons with
                      different spatial DOFs possess varying spectra. While
                      quantum optics applications often focus on either spatial or
                      spectral DOFs independently, the correlation between them
                      poses a fundamental challenge in protocols involving
                      entangled photon sources or single-mode photon states.
                      Theoretical studies on SPDC, that address both space and
                      spectrum together, are mostly limited to approximate wave
                      functions of photon pairs or involve numerical computations.
                      Such theoretical studies usually consider either
                      monochromatic signal and idler photons (the narrowband
                      approximation), loosely focused pump and collection beams
                      (the plane wave approximation), or infinitesimally thin
                      crystals (the thin crystal approximation). This dissertation
                      aims to bridge the gap between the fundamental theory of
                      SPDC and its practical applications. In particular, we have
                      developed a comprehensive theory that does not rely on a
                      specific pump beam or nonlinear crystal and goes beyond the
                      common narrowband, plane wave, and thin crystal
                      approximations. The developed approach accurately describes
                      the inseparability of spatial and spectral DOF and applies
                      to a wide range of experimental setups. Furthermore, we show
                      that the origin of the spatio-spectral coupling is closely
                      related to the Gouy phase of the interacting beams. We
                      utilize the developed theory, taking into account the
                      spatio-spectral coupling insights, to control the
                      entanglement of photon pairs from SPDC. As an application,
                      we shape the spatial distribution of the pump beam to design
                      an efficient source of high-dimensional entangled states in
                      the spatial DOF. In our second application, we tailor
                      simultaneously the effective nonlinearity of the crystal and
                      spatial distribution of the pump, to engineer single-mode
                      photons.},
      keywords     = {Parametrische Fluoreszenz (Other) / Photon (Other) / 530
                      (Other)},
      cin          = {JTH},
      cid          = {I:(DE-Ds200)JTH-20220701OR465},
      pnm          = {631 - Matter – Dynamics, Mechanisms and Control
                      (POF4-631)},
      pid          = {G:(DE-HGF)POF4-631},
      experiment   = {$EXP:(DE-Ds200)no_experiment-20200803$},
      typ          = {PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:gbv:27-dbt-20240212-103326-001},
      doi          = {10.22032/DBT.59567},
      url          = {https://repository.gsi.de/record/348992},
}